Background. Depressive disorders are quite common in patients with diabetes mellitus (DM). Depression is associated with worsening glycemic control. Attempts to improve it through the use of synthetic antidepressants in complex therapy have had mixed results. The study was aimed to evaluate the prevalence of depressive disorders in patients with diabetes mellitus treated in the endocrinology department and to evaluate the effect of combined herbal medicine Sedariston containing standardized extracts of Hypericum perforatum (100 mg) and Valeriana (50 mg) (Esparma GmbH, Germany) on carbohydrate metabolism and psycho-emotional state of diabetic patients with the anxiety-depressive syndrome. Materials and methods. The study included 122 patients with type 1 and 2 DM, 103 women and 19 men, aged 18 to 75 years. Thirty-three of them with anxiety-depressive syndrome participated in a 3-month study, 16 of which additionally received Sedariston 2 capsules twice a day for 2 months. Prior to, as well as 2 weeks, 1, 2, 3 months from the beginning of the observation, the psycho-emotional state was assessed with a determination of the severity of the depressive syndrome on the PHQ-9, Beck scales, as well as the state of personal and reactive anxiety on the Spielberger-Hanin’s scales. Glycated hemoglobin was determined before and 3 months after the start of monitoring. All patients received insulin therapy and/or hypoglycemic oral medications at constant doses during the observation. Results. Depressive disorders were identified in 80.3 and 67.2 %, respectively, according to the PHQ-9 and Beck scales. Most patients experienced mild and moderate depression. High personal anxiety was found in 66.4 %, high reactive anxiety in 50.8 % of patients. Patients in the Sedariston basic group reported significant improvement in depressive symptomatology with a decrease in PHQ-9 scores from 13.7 ± 1.6 to 9.3 ± 1.4 (p < 0.05) after 1 month of treatment, and on the Beck’s scale from 23.9 ± 1.8 to 18.2 ± 1.9 points (p < 0.05) after 2 months of treatment, in contrast to patients in the control group without Sedariston: 11.9 ± 1.2 and 10.8 ± 1.1 points (p > 0.1) on the PHQ-9 scale and 19.7 ± 1.7 and 18.9 ± 2.3 points (p > 0.1) on the Beck’s scale, respectively. The achieved improvement of the psycho-emotional state of patients after the end of treatment with Sedariston was maintained after 3 months from the beginning of monitoring: 7.1 ± 1.3 points on the PHQ-9 scale and 16.1 ± 2.1 points on the Beck’s scale (p < 0.01). After 2 months of Sedariston therapy in the group of patients with the anxiety-depressive syndrome, unlike the patients of the control group, personal anxiety decreased from 59.5 ± 2.2 to 53.5 ± 1.9 points on the Spielberger-Hanin’s scale (p < 0.05), in patients with high reactive anxiety, after 2 months of treatment significantly decreased its level from 57.4 ± 2.5 to 49.3 ± 2.7 points and remained so until the end of observation. Against the background of the positive dynamics of depressive symptoms in patients receiving Sedariston, a significant decrease in glycated hemoglobin occurred 3 months after the start of therapy: from 9.4 ± 0.5 to 8.1 ± 0.2 % (p < 0.05), unlike the patients of the control group. Conclusions. An anxiety-depressive syndrome is defined in 63.1 % of patients of the diabetology department, with depressive disorders mainly of mild and moderate severity, high personality and reactive anxiety, and 19.7 % of patients experienced a depressive syndrome without disturbance of anxiety, which indicates their diagnosis and conducting appropriate treatment. The combined phytopreparation Sedariston in the complex therapy of patients with diabetes mellitus, against the backdrop of the positive and long-lasting effect on anxiety-depressive symptoms, contributes to the improvement of carbohydrate metabolism, with a decrease of 1.3 % of glycated hemoglobin in 3 months. This indicates that Sedariston may be used not only for the treatment of anxiety-depressive syndrome but also to improve carbohydrate metabolism in patients with DM.